Wheel ends include a hub that is supported by wheel bearings for rotation on a spindle. A spindle nut pack is installed onto an end of the spindle and is adjusted as needed to provide a desired bearing end play amount which is typically within a range of 0.001 inches to 0.005 inches.
A conventional spindle nut pack includes an inner nut that is threaded onto the spindle end and abuts against an outer wheel bearing. An inner lock washer and bendable lock washer are installed onto the spindle end with the inner lock washer abutting against the inner nut. Finally, an outer jam nut is then jammed onto the inner nut. The bendable lock washer and jam nut are used for safety reasons to provide redundancy for retaining the inner nut on the spindle.
This traditional configuration is inexpensive and easy to install; however, it is difficult to precisely and consistently set a desired bearing end play. The inability to maintain the desired level of precision is due to the action of jamming the outer nut onto the inner nut, which moves the inner nut from its initial position to a position that is at an opposite flank of the respective threads of the threaded connection.
A single-nut configuration has been used to improve precision; however, these nuts are expensive and forfeit the safety redundancy of the conventional spindle nut pack. While the single-nut configuration is an improvement over the conventional spindle nut pack with regard to precision, distribution comparisons have shown that there are still a statistically significant number of installations that fall outside the desired limits. As such, both the conventional spindle nut pack and the single-nut configuration still require 100% auditing of endplay settings, which is time consuming and increases cost.